CCNA Cisco Certified Network Associate Study Guide - FTP Server

696 Glossary
packet switch A physical device that makes it possible for a communication
channel to share several connections, its functions include finding the
most efficient transmission path for packets.
packet switching A networking technology based on the transmission of
data in packets. Dividing a continuous stream of data into small units—
packets—enables data from multiple devices on a network to share the same
communication channel simultaneously but also requires the use of precise
routing information.
PAP Password Authentication Protocol: In Point-to-Point Protocol (PPP)
networks, a method of validating connection requests. The requesting
(remote) device must send an authentication request, containing a password
and ID, to the local router when attempting to connect. Unlike the more
secure CHAP (Challenge Handshake Authentication Protocol), PAP sends
the password unencrypted and does not attempt to verify whether the user
is authorized to access the requested resource; it merely identifies the remote
end. See also: CHAP.
parity checking A method of error-checking in data transmissions. An
extra bit (the parity bit) is added to each character or data word so that the
sum of the bits will be either an odd number (in odd parity) or an even
number (even parity).
partial mesh A type of network topology in which some network nodes
form a full mesh (where every node has either a physical or a virtual circuit
linking it to every other network node), but others are attached to only one
or two nodes in the network. A typical use of partial-mesh topology is in
peripheral networks linked to a fully meshed backbone. See also: full mesh.
PCR Peak Cell Rate: As defined by the ATM Forum, the parameter specifying,
in cells per second, the maximum rate at which a source may transmit.
PDN Public Data Network: Generally for a fee, a PDN offers the public
access to computer communication network operated by private concerns or
government agencies. Small organizations can take advantage of PDNs,
aiding them creating WANs without investing in long-distance equipment
and circuitry.
PGP Pretty Good Privacy: A popular public-key/private-key encryption
application offering protected transfer of files and messages.